1. Field of Invention
The current invention relates to adjustable wheelchairs, and more specifically to adjustable wheelchairs that easily adjust to the differences in a user's size and weight over time.
2. Description of Related Art
Many people (“users”) that have difficulty walking may require wheelchairs. Since some of these have chronic or degrading conditions, they may require a wheelchair for long periods of time, or even for the rest of their life.
Some of these users are children. If they are fitted for a wheelchair when they are small, they can quickly outgrow the wheelchair. Since insurance typically pays for the wheelchair, it is possible that the insurance company does not pay for another wheelchair, requiring the user to pay the bill. If the user chooses not to pay or is unable to pay for the replacement wheelchair, the user then is cramped into a wheelchair that is not the proper size.
In the alternative, a child user may be measured for a wheelchair, but given one that is several times larger than his/her measured size to compensate for growth. In this situation, the user now has to deal with a wheelchair that is higher, wider and heavier than the user needs.
Adult users may also require alternate positioning prior to the allotted time for a replacement wheelchair to be provided by insurance company. Due to changes in medical status, users may need larger or small wheelchairs throughout the disease process. However, most forms of insurance will only pay for a new mobility device once every five years. Therefore, adult users would also benefit from an adjustable wheelchair to meet their needs through the years.
Regardless of age, proper fitting wheelchairs are important to the safety and independence of users. If a wheelchair does not adequately meet the needs of the user, skin breakdown and other injuries may occur. A wheelchair that is too large may not provide adequate support to prevent falls from the wheelchair. Also, a wheelchair that is too small may cause pressure areas on users which could lead to skin breakdown and ultimately decreased independence due to new illnesses.
Since these users typically require the wheelchair almost everywhere they go, it must be transported with them. In order to easily transport the wheelchair, they are typically designed to be folded and fit into an automobile. They are also loaded into and taken out of cars, carried up steps, and across surfaces upon which they cannot travel. Therefore, the weight of the wheelchair is important. Since they are lifted many times a day, any weight reduction is multiplied by the number of times it is lifted and results in a significant energy savings over the course of the day.
Therefore, a chair larger than required results in a heavier wheelchair and a significant waste of energy lifting the wheelchair throughout the day.
In the alternative, if a properly sized wheelchair is used for a child, as the child grows, the wheelchair is not only too small, but may lack the required structural support as the user gets heavier.
There have been attempts at making adjustable wheelchairs.
U.S. Pat. No. 4,082,348, Apr. 4, 1978 Haury, and US Patent Application 2012/0126513 A1, May 24, 2012, Kent et al. describes an X-like configuration for an adjustable wheelchair. These employ cross members that have a tube which fits inside of another tube with holes at various locations. The tubes can be expanded so that the pins fit into the holes in the tubes at these fixed locations providing several fixed adjustment lengths to the size of the wheelchair. This does not provide adjustment to a given length, but only to the several pre-selected lengths which is used to approximate the proper desired width for the user. These also involve the adjustment of several structures.
U.S. Pat. No. 4,989,890, Feb. 5, 1991 Lockard et al. has a similar structure and similar problems.
U.S. Pat. No. 5,782,483, Jul. 21, 1998, Rogers et al. al. and US Patent Application 2013/0257009 A1, Oct. 3, 2013, Rogers describe an x-like configuration that is continuously adjustable. This requires simultaneous adjustment of two sliders in order to prevent binding when adjusting it.
U.S. Pat. No. 6,467,788 B1 Oct. 22, 2002, Li et al. describes a folding design, but is not intended to be adjustable.
U.S. Pat. No. 8,454,048 B1 Jun. 4, 2013 Regan et al. describes another folding design that is not intended to be adjustable.
The above designs do not adjust to support more weight or adjust to become lighter.
Currently, there is a need for a wheelchair with a simple design that would adjust to accommodate changes in the size and weight of the user over time.